A throttle controls the flow of air, or air and fuel, which are inducted into an internal combustion engine to thereby control the power produced by the engine. Engine power defines the speed of the engine or vehicle to which it is attached, under a given load condition, and thus, reliable control of the throttle setting is important. Vehicles are known to utilize throttle controls that are mechanical and electrical in nature. For example, off-road vehicles such as an ATV (All Terrain Vehicle) or a snowmobile operates with a small gasoline powered engine. To operate such engines, the operator activates a thumb lever or twist grip mounted on a handlebar that controls the engine throttle.
The thumb lever or throttle is usually mounted to and/or integrated with the right handlebar in order to control engine throttle. As the rider grips this handlebar, the rider's thumb operates the throttle by pushing the throttle against the handle bar and holding it in place. The throttle is designed to provide a range of speeds as the throttle is depressed. If the throttle is held fully open, the highest speeds can be attained. However, holding the throttle in between “off” and “full” produces an intermediate level of speed. To prevent the throttle from “sticking” in the open position, a spring is typically used to force the throttle back to the off position if the throttle is released.
In the majority of prior art designs, a direct mechanical linkage controls the throttle, typically in the form of a cable running from the thumb lever or twist grip to a throttle mechanism associated with the engine. Such throttle actuation is generally mechanical in nature and hence, the cable is subject to a great deal of wear and tear. Although mechanical linkages are simple and intuitive, such components cannot readily be adapted to electronically control an engine such as may be desired with sophisticated emissions reduction systems or for other features such as, for example, automatic vehicle speed control. The cable also tends to become stuck in adverse weather conditions such as, for example, snow, ice accumulation, driving on a dirt road, etc. Further, frequent servicing and monitoring of the throttle mechanism is required to maintain the device in proper working condition. Hence, it is believed that a solution to these problems involves the implementation of an improved drive-by-wire, throttle control apparatus associated with a variable resistance sensor, as described in greater detail herein.